Surface functionalized nano‐objects from oleic acid‐derived stabilizer via non‐polar RAFT dispersion polymerization

Abstract

Surface functionalization in a nanoscopic scaffold is highly desirable to afford nano‐particles with diversified features and functions. Herein are reported the surface decoration of dispersed block copolymer nano‐objects. First, side‐chain double bond containing oleic acid based macro chain transfer agent (macroCTA), poly(2‐(methacryloyloxy)ethyl oleate) (PMAEO), was synthesized by reversible addition‐fragmentation chain transfer (RAFT) polymerization and used as a steric stabilizer during the RAFT dispersion block copolymerization of benzyl methacrylate (BzMA) in n‐heptane at 70 °C. We have found that block copolymer morphologies could evolve from spherical micelles, through worm to vesicles, and finally to large compound vesicles with the increase of solvophobic poly(BzMA) block length, keeping solvophilic chain length and total solid content constant. Finally, different thiol compounds having alkyl, carboxyl, hydroxyl, and protected amine functionalities have been ligated onto the PMAEO segment, which is prone to functionalization via its reactive double bond through thiol‐ene radical reactions. Thiol‐ene modification reactions of the as‐synthesized nano‐objects retain their morphologies as visualized by field emission‐scanning electron microscopy. Thus, the facile and modular synthetic approach presented in this study allowed in situ preparation of surface modified block copolymer nano‐objects at very high concentration, where renewable resource derived oleate surface in the nanoparticle was functionalized. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017, 55, 263–273

Synthesis and electrokinetics of cationic spherical nanoparticles in salt-free non-polar media

“…PISA offers several advantages compared to conventional latex polymerization: various stabilizer blocks are straightforward to synthesize, nano-objects can be prepared as concentrated dispersions without requiring purification, and nanoparticles with desired morphologies and sizes can be reproducibly targeted. The PISA approach was originally devised to produce diblock copolymer nano-objects in water 43 but has been recently extended by us 44 – 51 and others 52 – 58 to non-polar solvents. 59 PISA enables the rational design of block copolymer nano-objects with various core-forming blocks, including poly(methyl acrylate), 52 – 54 poly(benzyl methacrylate), 44 – 47 , 49 , 51 , 58 poly(3-phenylpropyl methacrylate), 55 – 57 poly(benzyl acrylate), 48 poly( N -2-(methacryloyloxy)ethyl pyrrolidone), 50 and poly(phenyl acrylate) 60 cores.…”

Functional‐Polymer Library through Post‐Polymerization Modification of Copolymers Having Oleate and Pentafluorophenyl Pendants

“…Also, this double bond is inactive towards photoinitiated thiol‐ene reaction but active towards thermally initiated thiol‐ene reaction in the presence of higher concentrations of thiol and AIBN . Thus, the MAEO units in the copolymer were modified with thiol‐functionalized compounds through thiol‐ene reactions (Scheme ) . The thiol‐ene reaction is known to follow a radical pathway with an anti‐Markovnikov mechanism, in which the addition of a thiyl radical to a double bond is followed by chain transfer to thiol .…”

“…[32] Thus, the MAEO units in the copolymer were modified with thiol-functionalized compoundst hrough thiol-ene reactions (Scheme 1). [33] The thiolene reaction is knownt of ollow ar adical pathway with an anti-Markovnikov mechanism, in which the addition of at hiyl radicalt oad ouble bond is followed by chain transfer to thiol. [34] Thermally initiated thiol-ene modification was achieved herein with varioust hiols (RSH), such as 1-butanethiol, 1-thiob-d-glucose tetraacetate,2 -mercaptoethanol, 2-(dansylamino)ethanethiol and 2-(Boc-amino)ethanethiol.…”

Reactive and Functional Nanoobjects by Polymerization‐Induced Self‐Assembly

“…Another nonpolar surface-reactive PISA system was reported by De and coworkers. [44] Highly functionalized nanoobjects with one non-activated double bond per repeating unit in the shell were obtained by RAFTPISA of benzyl methacrylate (BzMA) in n-heptane in the presence of a homopolymer of (methacryloyloxy)ethyl oleate (MAEO; Scheme 2) as CTA. Pure sphere, worm-like, and vesicle phases could be achieved by varying the DP n of the PBzMA segment.…”